Preheat your oven to 350° F. Line a loaf pan with parchment paper.
In a large bowl, beat your butter and sugar until creamy. Add the eggs, vanilla and lemon juice and beat until incorporated.
In a medium bowl, whisk together the flour, baking soda, baking powder and salt.
Slowly add the dry to the wet, half a cup at a time, until all is incorporated. The dough will be stiff - thats ok.
Lastly, fold in your sour cream and mashed bananas until a smooth silky batter exists. DO NOT OVER MIX.
Transfer batter to your loaf pan, spread out evenly and bake for 1 hour or until toothpick comes out clean. Allow it to cool 10 minutes in pan and then another 15 minutes on a cooling rack.